1. Field of the Invention
This invention pertains to a hay making machine, especially a fodder swather, which includes a carrying structure that can be connected to a tractor, the structure supporting at least one rotor which can turn about a support axle which is approximately vertical, and to which two beams are connected, with each one having two carrying wheels.
2. Description of the Related Art
On a machine of this kind the beams allow one to reduce the extent of the displacements transmitted to the rotor when the carrying wheels pass over uneven places. Consequently, said rotor adapts better to the surface of the ground and can be displaced at greater speed.
However, during turns the wheels skid over the ground. They are then subjected to considerable wear and they can damage the vegetation on the surface of the ground. This skidding arises from the fact that they are offset with respect to one another in the direction of advance. To remedy this it has been proposed to make one or both carrying wheels of each pair pivot with respect to their beam about approximately vertical axes. In this case the beam must be located above one or both pivoting carrying wheels so that they can have room to turn about said axes. However, because the height available under each rotor is limited by the hub and/or the tool carrying arms of this rotor, it is only possible to use pivot-mounted wheels having a small diameter. Such wheels do not move as well over irregular ground and are not suitable to be used on large-size machines. In addition, in order to make these wheels pivot-mounted it is necessary to mount each one on an arm which must be articulated on the corresponding beam. Such implementation is relatively complicated and expensive.
Moreover, the pivot-mounted wheels easily deviate from their trajectory when they meet obstacles. It might happen, therefore, that the carrying wheels which are arranged under the same rotor are not always oriented in the same direction. In this case they skid or slide along the ground and destabilize the machine.